Methods, apparatus and products for filtering

ABSTRACT

A device for filtering a gas stream, having a vessel partitioned into a first stage and a second stage, with an opening between stages. A filter element is positioned in the opening, with ends of the filter element extending into the first and second stages. The first member is removable from the second member while the filter element is positioned in the opening, to allow for replacement with a new clean member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to methods, apparatus and products forfiltering. In another aspect, the present invention relates to methods,apparatus and products for filtering streams of gas and/or liquids toremove solids and/or entrained liquids. In even another aspect, thepresent invention relates to methods, apparatus and products forfiltering, utilizing a filter system in which that portion of the filtersystem more likely to accumulate filtrate is replaceable apart from thatportion of the filter system which is less likely to accumulatefiltrate. In even another aspect, the present invention relates tomethods, apparatus and products for filtering, utilizing a two stagefilter system in which that portion of the filter system in the firststage is more likely to accumulate filtrate is replaceable apart fromthat portion of the filter system in the second stage which is lesslikely to accumulate filtrate.

2. Brief Description of the Related Art

There are a number of applications in which it is necessary to removesolids or liquids from a gas stream, liquid stream, or multi-phasestream. As a non-limiting example, solid or liquid contaminants may bepresent in various gas or liquid streams of a refrigeration system. Asanother non-limiting example, gas pipelines many times contain solid orliquid contaminants.

Various apparatus and methods for removing solids and/or liquids fromgas streams are well known. Quite commonly, gas filter elements areutilized for filtering dry gas streams as well as for separating solidsand liquids from contaminated gas streams, or for coalescing entrainedliquids from a gas stream. Often these types of gas filter elements areinstalled in multi-stage vessels, which are in turn installed in a gaspipeline, to perform these filtering functions.

There are a number of patents that relate to removing solids and/orliquids from gas streams, the follow of which are merely a smallsampling.

U.S. Pat. No. 6,381,983, issued May 7, 2002, to Angelo et al., disclosesan improved filter drier for a refrigeration system having a replaceabletubular filter element. A desiccant assembly is removably secured withina housing. The assembly includes a first and second molded desiccant, ahollow tubular perforated core located within said first and secondmolded desiccant, and a tubular filter located over said core.

U.S. Pat. No. 6,692,639, issued Feb. 17, 2004, to Spearman et al.,discloses a conically shaped filtration and/or separation apparatus thatis constructed from a stack of filters at least some of which aredifferent sizes superposed above each, other, of said plurality of saidfilters in a fluid communicable relationship. A collapsible version ofsuch conically shaped filter and/or separation apparatus is providedwhereby a plurality of such filters are connected together using twopiece interlocking or connecting end caps.

U.S. Pat. No. 6,858,067, issued Feb. 22, 2005, to Burns et al.,discloses a filtration vessel for use with a rotary screw compressorthat receives a compressed liquid/gas mixture from the compressor. Thevessel utilizes a first stage vortex knockout region to remove bulkliquids through a circular motion that imposes centrifugal forces on thegas and liquid mixture. A coalescer region located above the vortexknockout region receives the relatively lighter fluids and separates anyremaining entrained liquids from the fluids. The discharge from thefiltration unit is an essentially liquid free compressed gas. The liquiddischarge, in the case of lube oil can be recirculated to the compressorfor another cycle.

U.S. Pat. No. 7,051,540, issued May 30, 2006, to TeGrotenhuis et al.,discloses a wick-containing apparatus capable of separating fluids andmethods of separating fluids.

U.S. Patent Application Publication No. 20070095746, published May 3,2007 to Minichello et al., discloses an apparatus for filtering a gas orliquid stream such as a natural gas stream. The apparatus includes aclosed vessel having a longitudinally extending length, an initiallyopen interior, an inlet port at one extent and an outlet port at anopposite extent thereof. A partition located within the vessel interiordivides the vessel interior into a first chamber and a second chamber.At least one opening is provided in the partition. A filter element isdisposed within the vessel to extend from within the first chamber. Aspecial seal structure formed of a resilient material and havingconically shaped sidewalls is used to seal against one end of the filterelement as well as forming a dynamic seal with the vessel riser in use.

U.S. Pat. No. 7,270,690, issued Sep. 18, 2007, to Sindel, discloses aseparator vane assembly made up of a number of corrugated vanes thatprovide serpentine paths for the gas stream therethrough. As the gasstream flows through the serpentine paths, it changes direction andliquid in the gas stream impacts the surfaces of the vanes. The upstreamsection of the vane assembly has roughened surfaces to decrease thesurface tension of the liquid, thereby causing the liquid to coalesce.The downstream section of the vane assembly has smooth surfaces so as toincrease the surface tension of the liquid. The vane assembly isfollowed by filters, which capture the liquid that passes through thevane assembly. The vane assembly coalesces the liquid to enable thefilters to operate more effectively.

U.S. Patent Application Publication No. 20070251876, published Nov. 1,2007 to Krogue et al., discloses an apparatus for filtering a gas orliquid stream of impurities and to filter elements used in such anapparatus. The apparatus includes a closed vessel having alongitudinally extending length, an initially open interior, an inputport at one extent and an output port at an opposite extent thereof. Apartition located within the vessel interior divides the vessel interiorinto a first stage and a second stage. At least one opening is providedin the partition. A filter element is disposed within the vessel toextend from within the first stage. The filter element is made up of acarbon block filter media surrounded by a protective porous depth filtermedia.

U.S. Pat. No. 7,314,508, issued Jan. 1, 2008, to Evans, discloses adesiccant cartridge having a seal therearound for forming a proper sealbetween the cartridge and the canister of a receiver/dryer oraccumulator assembly includes a cup extending along an axis having innerwall portion and outer wall portion connected to a transverse portion todefine a chamber containing desiccant particles. A cap is secured to cupto secure the desiccant particles inside the chamber. The outer wallportion is provided with the seal that is composed of a flexiblethermoplastic elastomer that is resistant to heat during welding shut ofthe canister.

U.S. Pat. No. 7,332,010, issued Feb. 19, 2008, to Steiner, discloses atwo or three phase separator including a centrifugal separator, ademister (if a three phase separator), and a filter contained within ahousing. The filter uses an outside-in flow principle. The filterincludes an inner layer or a center core that defines a hollow interior.An outer layer is positioned adjacent and surrounding the inner layer.The outer layer includes a re-enforcement layer, a first particle filterlayer, a coalescer layer, and a second particle filter layer. An accesscover of the separator includes a cover plug, an actuator cam, aplurality of idler cam plates, and a plurality of mechanisms. The accesscover cooperates with an opening and an annular groove in the housing toclose off and seal the separator.

U.S. Pat. No. 7,344,576, issued Mar. 18, 2008, to TeGrotenhuis et al.,discloses methods of separating fluids using capillary forces and/orimproved conditions. The improved methods may include control of theratio of gas and liquid Reynolds numbers relative to the Suratmannumber. Also disclosed are wick-containing, laminated devices that arecapable of separating fluids.

Quite commonly in pipeline applications, it is not uncommon to seemulti-stage vessels, as well as a multitude of other similar filtrationvessels, that utilize solid or hollow core tubular elements, typicallyformed at least partially a porous filtration media. Non-limitingexamples of such vessels include filtration equipment such as shown inU.S. Pat. No. 5,919,284, issued Jul. 6, 1999 or U.S. Pat. No. 6,168,647,issued Jan. 2, 2001, both to Perry, Jr. et al.

U.S. Pat. No. 5,919,284 discloses a gas filter separator coalescer andmulti-stage vessel for separating liquids and solids from a gas streamand simultaneously coalescing liquids from the gas stream. The apparatusincludes a closed vessel having a longitudinally extending length, aninitially open interior, an input port at an extent and an output portat an opposite extent thereof. There is a partition located within thevessel interior that divides the vessel interior into a first stage anda second stage. There is at least one opening in the partition. Aseparator/coalescer filter element is disposed within the vessel tosealingly extend from within the first stage through the opening intothe second stage. There is a chevron-type seal or an O-ring seal betweenthe filter element and the opening. The input port, vessel interior,separator/coalescer filter element and output port together define aflow passage within the apparatus, whereby the gas stream flows into thefirst stage through the input port and through the filter element hollowcore, thereby filtering solids out of the gas stream, separating liquidsfrom the gas stream, and pre-coalescing liquids in the gas stream. Thegas stream then flows along the hollow core past the partition and backthrough the filter element into the second stage, thereby coalescingliquids out of the gas stream, the gas stream then exiting the secondstage through the outlet port.

U.S. Pat. No. 6,168,647 discloses an apparatus for separating liquidsand solids from a gas stream and simultaneously coalescing liquids fromthe gas stream. The apparatus includes a closed vessel having alongitudinally extending length, an initially open interior, an inputport at an extent and an output port at an opposite extent thereof.There is a partition located within the vessel interior that divides thevessel interior into a first stage and a second stage. There is at leastone opening in the partition. A separator/coalescer filter element isdisposed within the vessel to sealingly extend from within the firststage through the opening into the second stage. There is a chevron-typeseal or an O-ring seal between the filter element and the opening. Theinput port, vessel interior, separator/coalescer filter element andoutput port together define a flow passage within the apparatus, wherebythe gas stream flows into the first stage through the input port andthrough the filter element hollow core, thereby filtering solids out ofthe gas stream, separating liquids from the gas stream, andpre-coalescing liquids in the gas stream. The gas stream then flowsalong the hollow core past the partition and back through the filterelement into the second stage through a louvered impingement baffle,thereby coalescing liquids out of the gas stream, the gas stream thenexiting the second stage through the outlet port. The louveredimpingement baffle conditions the gas stream to create a scrubbingeffect on any fine mist exiting the separator/coalescer filter element.

With such equipment as disclosed in the U.S. Pat. No. 5,919,284 or6,168,647, it is periodically necessary to perform maintenance on thefiltration vessels, including replacement of the porous filter elements.This task is labor intensive and time consuming insitu because of themounting structure used to mount the filter elements within thefiltration vessel interior. Often, it is necessary to unscrew the endcap or nut to free the filter element from its associated structuralmounting within the vessel interior. Not only is this time consuming,but the location of the mounting structure is sometimes inconvenient toaccess, making filter replacement a difficult or inconvenient chore. Thesame type of inconveniences is present in the initial filterinstallation process for new filtration vessels.

Specifically for filter systems of the type disclosed in U.S. Pat. No.6,168,647, there are at least two reasons for the difficulty in removingthe filter elements. First, the chevron seal is working against theremoval direction when trying to remove the element. Second, since thefilter element extends into the riser assembly, solids collect and packinto the riser assembly. Additionally, it is not uncommon to find damageto the downstream expanded metal support grid generally caused by theelements being shoved in too far.

In an effort to overcome the problems of the prior art, especially thedeficiencies of U.S. Pat. No. 5,919,284 or 6,168,647, furtherdevelopment was advanced in U.S. Pat. No. 7,014,685, issued Mar. 21,2006, and U.S. Pat. No. 7,108,738, issued Sep. 19, 2006, both to Burnset al. These two patents disclose an apparatus for filtering a gas orliquid stream such as a natural gas stream. The apparatus includes aclosed vessel having a longitudinally extending length, an initiallyopen interior, an input port at one extent and an output port at anopposite extent thereof. A partition located within the vessel interiordivides the vessel interior into a first stage and a second stage. Atleast one opening is provided in the partition. A filter element isdisposed within the vessel to extend from within the first stage. Thefilter element is easily mounted or removed from the vessel by rotatinga J-slot engagement surface on the element which mates with a postprovided on a mounting structure provided on the vessel partition.

However, in spite of the above advancements that have been made inoverall filtration vessel design, there still exists a need in art forapparatus and methods for filtration.

There also exists a need in the art for apparatus and methods forimprovements that simplify the process of mounting and replacing filterelements within the filtration vessel, thereby decreasing the cost ofvessel installation and maintenance.

As a non-limiting example of a desired improvement, for filtrationsystems as disclosed in U.S. Pat. Nos. 5,919,284, and 6,187,647, theportion of the filter element positioned in the downstream stage isgenerally a lot cleaner than the portion of the filter elementpositioned in the upstream stage. However, with these filtrationsystems, the entire filter element is removed and replaced, even thoughthe downstream portion of the filter may be readily further used.

These and other needs in the art will become apparent to those of skillin the art upon review of this specification, including its drawings andclaims.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide for apparatus andmethods for filtration.

It is another object of the present invention to provide for apparatusand methods for improvements that simplify the process of mounting andreplacing filter elements within the filtration vessel, therebydecreasing the cost of vessel installation and maintenance.

It is even another object of the present invention to allow the use ofdifferent removal efficiencies of filter elements in the first andsecond stages based on the application and/or operator's requirements.

These and other objects of the present invention will become apparent tothose of skill in the art upon review of this specification, includingits drawings and claims.

According to one embodiment of the present invention there is providedan apparatus for filtering a gas. The apparatus may include a vesselhaving a partition dividing the vessel into a first stage and a secondstage, wherein the partition defines an opening providing liquidcommunication between the stages. The apparatus also may include afilter element positioned in the opening comprising first member havinga first connection end and a second member having a second connectionend. This the first and second members may be connected by a connectionsystem in which the first connection end and the second connection endform a mating pair to provide the connection, wherein at least a portionof the first member extends into the first stage, and at least a portionof the second member extends into the second stage, and wherein thefirst member is removable from the second member while the filterelement is positioned in the opening.

According to another embodiment of the present invention, there isprovided a method of operating a filtering apparatus. The filteringapparatus may comprise a vessel having a partition dividing the vesselinto a first stage and a second stage, wherein the partition defines anopening providing liquid communication between the stages, and furthercomprises a filter element positioned in the opening comprising a firstmember having a first connection end and a second member having a secondconnection end, wherein the first and second members are connected by aconnection system in which the first connection end and the secondconnection end form a mating pair to provide the connection, wherein atleast a portion of the first member extends into the first stage, and atleast a portion of the second member extends into the second stage. Themethod may include separating the first member from the second member,while the filter element is positioned in the opening, thereby leavingat least a portion of the second member extending into the second stage.

According to even another embodiment of the present invention, there isprovided a method of operating a filtering apparatus. The filteringapparatus may comprise a vessel having a partition dividing the vesselinto a first stage and a second stage, wherein the partition defines anopening providing liquid communication between the stages, and furthercomprises a filter element positioned in the opening comprising a firstmember having a first end and a second member having a second connectionend, wherein the first and second members are connected by a connectionsystem in which the first connection end and the second connection endengage to provide the connection, wherein at least a portion of thefirst member extends into the first stage, and at least a portion of thesecond member extends into the second stage. The method may includereplacing the first member with a replacement member.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings illustrate some of the many possible embodimentsof this disclosure in order to provide a basic understanding of thisdisclosure. These drawings do not provide an extensive overview of allembodiments of this disclosure. These drawings are not intended toidentify key or critical elements of the disclosure or to delineate orotherwise limit the scope of the claims. The following drawings merelypresent some concepts of the disclosure in a general form. Thus, for adetailed understanding of this disclosure, reference should be made tothe following detailed description, taken in conjunction with theaccompanying drawings, in which like elements have been given likenumerals.

FIG. 1 is a schematic representation of one non-limiting embodiment of afiltration system of the present invention.

FIG. 2 is a schematic representation of a filter element of the presentinvention.

FIG. 3 shows engaging member 139 of first filter member 124 resides inslot 136 of second filter member 125.

FIG. 4 shows first filter member 124 and second member 125 have beentwisted relative to each other to allow engaging member 139 to move inslot 136 toward slot opening 137 to allow for disengagement.

FIG. 5 shows first filter member 124 and second member 125 have beenfurther twisted relative to each other, such that engaging member 139 isshown aligned in slot opening 137 to allow for disengagement.

FIG. 6 shows first filter member 124 and second member 125 have beenmoved away from each other, such that engaging member 139 is shownmoving though slot opening 137 to allow for disengagement.

FIG. 7 shows first filter member 124 and second member 125 have beenmoved away from each other, such that engaging member 139 is shown movedcompletely through slot opening 137 and filter members 124 and 125 aredisengaged.

FIGS. 8-10 show slightly different views of filter 120, showing filtermembers 124 and 125 disengaged.

DETAILED DESCRIPTION OF THE INVENTION

In one aspect, the present invention provides a filtration filter. Inanother aspect, the present invention provides a filtration system thatincludes the filtration filter positioned within a filtration vessel.Any suitable type of filtration vessel may be utilized in the practiceof the present invention, including certain filtration vessels asdisclosed in any of U.S. Pat. Nos. 5,919,284, 6,187,647, 7,014,685, and7,108,738. Depending upon the situation and operating conditions,suitable filtration vessels may include multi-stage vessel 11 as shownin FIG. 1 of U.S. Pat. No. 6,187,647, and filter vessel 13 as shown inFIG. 1 of U.S. Pat. No. 7,014,685, with the understanding that vessels11 and 13 will include the filtration filter as disclosed herein, and beadapted to receive such filter.

Referring now to FIG. 1, there is shown a schematic representation ofone non-limiting embodiment 100 of the filtration system of the presentinvention. In very simple terms, the filtration system of the presentinvention may include a filtration vessel 102 having a first stage 104and a second stage 105. A partition 108 positioned within filtrationvessel 102 divides the volume of filtration vessel 102 into first stage104 and second stage 105. The present invention anticipates that in somenon-limiting embodiments, filtration vessel may comprise two vesselsthat are joined together, one vessel forming the first stage, and onevessel forming the second stage, with the abutted walls of each vesselserving as the partition, or perhaps the two vessels will share a commonwall serving as the partition.

Partition 108 defines at least one passage 111 allowing for liquidcommunication between first stage 104 and second stage 105. Within eachof passages 111 will reside a filtration filter 120. This filter 120includes at least two distinct parts, first filtration member 124 andsecond filtration member 125. Filter member 120 may in some embodimentsbe a hollow core filtration filter. In some non-limiting embodiments, atleast a portion of first filtration member 124 will extend into vesselfirst stage 104, and at least a portion of first member 124 will extendinto vessel second stage 105. In some non-limiting embodiments, none offirst filtration member 124 will extend into vessel second stage 105.

It should be understood that first filtration member 124 and secondfiltration member 125 may provide the same or different filtering, thatis, the filtering characteristic of the first and second filtrationmembers 124 and 125 may be the same or different. As a non-limitingexample, first filtration member 124 may have a first filteringcharacteristic wherein it removes larger particles and allows smallerparticles to be removed by filtration member 125 having a secondfiltering characteristic wherein it removed smaller pariticles. Itshould also be understood that when multiple filter members 120 areutilized, each of the multiple filter members 124 and 125 may be thesame or different. As a non-limiting example, various same and/ordifferent filter members 120 may be utilized based on the geometry ofthe arrangement of the filter members 120, based on the geometry of thevessel 102, and/or based on any other operating parameter or physicalproperty of the material being filtered. It should also be understoodthat filter member 120 may also include multiple stages that align withmultiple stages in a vessel 102. The filter member 120 may includemating pairs 130 at the interface of one or more or all of theinterfaces between stages, which mating pairs 130 may be the same ordifferent, and this filter member 120 may be disconnectable at one ormore the mating pairs 130.

Filtration vessel 102 further includes an inlet port 184 in fluidcommunication with vessel first stage 104. Filtration vessel 102 evenfurther includes an outlet port 185 in fluid communication with vesselsecond stage 105.

Gas flow, indicated by the “G” labeled arrows, is through inlet port 184and into vessel first stage 104, through the filter wall of filtermember 124, through the hollow core of filter member 124, into thehollow core of filter member 125, out through the wall of filter member125, through the second stage 105, and finally exiting through outlet185.

Referring additionally to FIG. 2, there is shown a schematicrepresentation of filter element 120 of the present invention. Referringeven additionally to FIGS. 3-10, there is illustrated various views offilter element 120 showing first member 124 and second member 125 invarious states of connection. Filter member 124 and filter member 125are joined by a mating pair 130 having a first pair member 134 at end124A of filter member 124, and a second pair member 135 at end 125A offilter member 125. In some embodiments, the mating pair 130 willcomprise male and female connector members. It should be understood thatfirst pair member 134 may comprise either a male or female connectormember, with second pair member 135 comprising the complimentary matingfemale or male connector member. In most embodiments, a female-malearrangement for the first and second pair members 134 and 135 will beconsidered equivalent to a male-female arrangement. This mating pair 130must sufficiently join filter member 124 and 125 together so as toendure the hardships of the filtration operation, but must allowdisconnecting of filter member 124 to allow for removal of such filtermember 124. As non-limiting examples, mating pair 130 may connect bysnapping, bolting, friction fitting, interlocking, engaging, coupling,hook/looping, adhering, adhesion with a time released adhesive, adhesionwith a solvent releasing adhesive, magnetic coupling, locking,threadably engaging, and the like.

In FIG. 3, engaging member 139 of first filter member 124 resides inslot 136 of second filter member 125. As shown, engaging member 139resides in end 138 of slot 136. Generally, twisting/untwisting ofmembers 124 and 125 relative to each other would lock engaging member139 in place at end 138 or could move it toward slot opening 137 fordisengagement. As a non-limiting embodiment, end 138 of slot 136 may beshaped (for example tapered) to provide a friction fit of engagingmember 139, or the surfaces of slot 136 at end 138 may betextured/roughened to engage textured/roughened surfaces of engagingmember 139. Untwisting them will reverse the process and allow for themembers to be separated.

Referring now to FIG. 4, first filter member 124 and second member 125have been twisted relative to each other to allow engaging member 139 tomove in slot 136 toward slot opening 137 to allow for disengagement.

Referring now to FIG. 5, first filter member 124 and second member 125have been further twisted relative to each other, such that engagingmember 139 is shown aligned in slot opening 137 to allow fordisengagement.

Referring now to FIG. 6, first filter member 124 and second member 125have been moved away from each other, such that engaging member 139 isshown moving though slot opening 137 to allow for disengagement.

Referring now to FIG. 7, first filter member 124 and second member 125have been moved away from each other, such that engaging member 139 isshown moved completely through slot opening 137 and filter members 124and 125 are disengaged.

FIGS. 8-10 show slightly different views of filter 120, showing filtermembers 124 and 125 disengaged.

In methods of the present invention, with filter element positionedwithin a filter vessel 102, filter member 124 may be separated fromfilter member 125, removed from vessel 102, and then replaced with a newfilter member.

All of the patents and applications cited in this specification, areherein incorporated by reference.

It should be understood that while the present invention has beenillustrated mainly by reference to filtration of a gas stream, it findsutility in the filtration of gas streams, liquid streams, and gas/liquidstreams.

The present disclosure is to be taken as illustrative rather than aslimiting the scope or nature of the claims below. Numerous modificationsand variations will become apparent to those skilled in the art afterstudying the disclosure, including use of equivalent functional and/orstructural substitutes for elements described herein, use of equivalentfunctional couplings for couplings described herein, and/or use ofequivalent functional actions for actions described herein. Anyinsubstantial variations are to be considered within the scope of theclaims below.

The invention claimed is:
 1. An apparatus for filtering a gas comprisinga vessel defining a volume, said vessel having a partition dividing thevolume of the vessel into an upstream first stage and a downstreamsecond stage, wherein the partition defines an opening providing liquidcommunication between the stages; and, a filter element positionedcompletely in the vessel in the first stage, the second stage and in theopening, the filter element comprising a first member having a firstconnection end and a first filtering characteristic, and a second memberhaving a second connection end and a second filtering characteristic,wherein the first and second members are connected by a connectionsystem in which the first connection end and the second connection endform a mating pair to provide the connection, wherein at least a portionof the first member extends into the first stage, and at least a portionof the second member is positioned in the first stage and extendsthrough the opening and into the second stage, wherein the first memberis removable from the second member while the second member remainspositioned in the first stage extending through the opening andpositioned in the second stage, and wherein the first filteringcharacteristic and the second filtering characteristic are the same ordifferent.
 2. The apparatus of claim 1, wherein the first and secondconnection ends form a mating pair by at least one of snapping, bolting,friction fitting, interlocking, engaging, coupling, hook/looping,adhering, adhesion with a time released adhesive, adhesion with asolvent releasing adhesive, magnetic coupling, locking, and threadablyengaging.
 3. The apparatus of claim 1, further comprising a replacementmember for the first member.
 4. The apparatus of claim 1, wherein thefirst connection end and the second connection end comprise an engagingmember and a slot adapted to receive the engaging member.
 5. Theapparatus of claim 1, wherein the first filtering characteristic and thesecond filtering characteristic are different.
 6. An apparatus forfiltering a gas comprising a vessel defining a volume, said vesselhaving a partition dividing the volume of the vessel into an upstreamfirst stage and a downstream second stage, said vessel defining a gasentry into the vessel at the first stage and defining a gas exit fromthe vessel at the second stage, wherein the partition defines an openingproviding liquid communication between the stages; and, a filter elementpositioned completely in the vessel in the first stage, the second stageand in the opening, the filter element comprising a first member havinga first connection end and a first filtering characteristic, and asecond member having a second connection end and a second filteringcharacteristic, wherein the first and second members are connected by aconnection system in which the first connection end and the secondconnection end form a mating pair to provide the connection, wherein atleast a portion of the first member extends into the first stage, and atleast a portion of the second member is positioned in the first stageand extends through the opening and into the second stage, wherein thefirst member is removable from the second member while the second memberremains positioned in the first stage extending through the opening andpositioned in the second stage, and wherein the first filteringcharacteristic and the second filtering characteristic are the same ordifferent.
 7. The apparatus of claim 6, wherein the first and secondconnection ends form a mating pair by at least one of snapping, bolting,friction fitting, interlocking, engaging, coupling, hook/looping,adhering, adhesion with a time released adhesive, adhesion with asolvent releasing adhesive, magnetic coupling, locking, and threadablyengaging.
 8. The apparatus of claim 6, further comprising a replacementmember for the first member.
 9. The apparatus of claim 6, wherein thefirst connection end and the second connection end comprise an engagingmember and a slot adapted to receive the engaging member.
 10. Theapparatus of claim 6, wherein the first filtering characteristic and thesecond filtering characteristic are different.
 11. An apparatus forfiltering a gas comprising a vessel defining a volume, said vesselhaving a partition dividing the volume of the vessel into an upstreamfirst stage and a downstream second stage, wherein the partition definesan opening providing liquid communication between the stages; and, afilter element positioned completely in the vessel in the first stage,the second stage and in the opening, the filter element comprising afirst member, having a first exterior, a first interior, a firstconnection end and a first filtering characteristic, and a second memberhaving a second exterior, a second interior, a second connection end anda second filtering characteristic, wherein the first and second membersare connected by a connection system in which the first connection endand the second connection end form a mating pair to provide theconnection, wherein at least a portion of the first member extends intothe first stage, and at least a portion of the second member ispositioned in the first stage and extends through the opening and intothe second stage, wherein the first member is removable from the secondmember while the second member remains positioned in the first stageextending through the opening and positioned in the second stage, andwherein the first filtering characteristic and the second filteringcharacteristic are the same or different; wherein a flow path is definedas entering the vessel directly at the first stage, passing from thefirst exterior to the first interior, passing into the second stage intothe second interior, passing from the second interior to the secondexterior, and then exiting the vessel directly from the second stage.12. The apparatus of claim 11, wherein the first and second connectionends form a mating pair by at least one of snapping, bolting, frictionfitting, interlocking, engaging, coupling, hook/looping, adhering,adhesion with a time released adhesive, adhesion with a solventreleasing adhesive, magnetic coupling, locking, and threadably engaging.13. The apparatus of claim 11, further comprising a replacement memberfor the first member.
 14. The apparatus of claim 11, wherein the firstconnection end and the second connection end comprise an engaging memberand a slot adapted to receive the engaging member.
 15. The apparatus ofclaim 11, wherein the first filtering characteristic and the secondfiltering characteristic are different.